Rotary drier



April 25, 1944. KIRCHMANNfJR ROTARY DRYER Filed July 13, 1940 lmlmH..

. I 'Il I Patented Apr. 25, 1944 ROTARY DRIER Y Henry Kirchmann, Jr., San Francisco, Calif., assignor of one-half to Alfred N. Warburton, Oakland, Calif.

Application July 13, 1940, Serial No. 345,382(

3 claims. (01.-34-142) My invention relates to means for drying various commodities,v particularly finely divided products, and is concerned especially with means for facilitating the rapid and economical drying of such materials.`

It is an object of my invention to provide a generally improved rotary drier.

The foregoing and other objects are attained in the embodiment of the invention illustrated in the drawing, in which- Fig. 1 is a cross-section, on a vertical longitudinal plane, through a rotary drier in accordance with my invention;

Fig. 2 is a cross-section the plane of whichA is indicated by the line 2--2 of Fig. 1; and

Fig. 3 is a cross-section similar to Fig. 2 but showing a modif-led form of flue arrangement.

In its preferred form, the rotary drier of my invention includes an inner drum and an outer drum which are rotated in unison during the time that material to be dried passes therethrough, such material being under the control of an inlet valve at one end of the outer drum and a discharge valve at the other end of the outer drum, the inner drum being in a generally closed circuit including a furnace disposed adjacent one end of the inner drum and having a conduit providing means for returning exhaust fluid from the inner drum to the furnace, there being a discharge opening for release of circulated uid as well as an inlet opening for the admission of atmospheric air to the furnace.

In its preferred form, my rotary drier is mounted on a suitable foundation 6, such as a oor, from which are upstanding pedestals I and 8. The pedestals are of different heights and act as supports for rollers 9 engaging circumferential rings II encompassing an outer drum I2. 'Ihis outer drum is circular in cross-sectional contour, preferably, and adjacent one of the bands II carries a ring gear I3 meshing with a pinion I4 extending to any suitable source (not shown) of rotary driving energy. One end of the outer drum I2 is received within a header or jacket I6 making close running fit with the drum so that the drum can rotate with respect thereto with only a minimum of leakage. The jacket I6 is provided with an inlet valve II which comprises a generally circular-cylindrical body with a vaned rotor I8 therein driven by a chain I9 from a. feed conveyor 2I. This conveyor is propelled in any suitable fashion and brings the material to be dried and discharges such material into the valve II. The material is then passed through the valve with the admission of only small amountsof outer air and without permitting the free escape of the contents of the outer drum.A The material passes through the jacket I6 into the outer drum I2 and, as such drum rotates, the material gradually gravitates toward the opposite end thereof because the drum is disposed with its central axis inclined to the horizontal. Having traversed the entire length of the outer drum I2, the material enters a discharge jacket 22 ,which is stationary and which serves as a convenient member for the junction of a suction outlet, 23 so that a subatmospheric pressure can be maintained within the outer drum I2. The jacket 22 is provided with an outlet valve 24 having vanes 26 therein which are suitably driven through a chain 2'I by a discharge conveyor 28, so that material released from the outer drum passes through the valve 24 Without admitting surplus exterior air and without permitting the escape of an unusual quantity of material, and is carried away on the belt 28 to any suitable point.

In order to increase the temperature within the outer drum during the traverse of material therethrough, to facilitate the drying operation, I dispose a furnace 3| at one end of the mechanism, which is supported on the floor 6. A suitable burner 33 supplies fuel, and a damper 34 admits a regulated quantity of atmospheric air to support combustion, The products of combustion pass from the furnace 3l and through an expansion section 35 into an inner drum 3l. The inner drum includes a cylindrical envelope extending between a pair of heads 38 and 39 disposed coaxially within the outer drum I2, which heads are joined by a plurality of flues 4I. These iues either are composed of pipes having a circularcylindrical cross-section as shown in Fig. 2 or, preferably, as shown in Fig. 3 are constituted by tubes 4I having a geometrical cross-section approximating a lozenge, so that a large amount of flat surface is presented for the momentary deposit of material to be dried thereupon. The inner drum 31 is supported within the outer drum by diametrical struts 43 extending therebetween, so that as the outer drum I2 rotates, the inner one rotates in unison therewith. The inner drum 3l, beyond the header 39, that is, at its opposite end, continues with the reduced portion 44 communicating with the inlet 46 of an exhaust blower 41 driven from any suitable source 48 and effective to Withdraw the gaseous contents of the inner drum and discharge them through a conduit i9 which extends back to the inlet 5I of the :furnace adjacent the air damper 34. At a suitable point in its length the conduit 49 has a discharge outlet 52 controlled by a manually adjustable damper 53, so that some portion of the returned gases can be discharged while atmospheric air is freely admissible through the dampers 34 to be admixed with the returned warm gases 5I for recirculation* In the general operation of this structure, as the furnace functions and the blower 41 assists in drawing warm gases through the inner drumthat is, through the ues 4l or 4I included in such drum-and `continues to recirculate such warm gases, the material passing between the outer drum and the inner drum is placed in contact with the hot surfaces and is deprived of its connected to said flues, a feed conveyor, a material feeding valve disposed to discharge material from said feed conveyor into one end of said drum, means for driving said feed conveyor and said feeding valve in unison, a discharge valve and a conveyor receiving material from said discharge valve.

2. A rotary 4drier comprising a rotatable drum, longitudinally extending heating ues mounted to rotate with said drum, a source lof heat supply connected to said nues, afeed conveyor, amaterial feeding valve disposed to discharge material from said feed conveyor into one end of said drum, means for driving said feed vconveyor and said feeding valve in unison, a discharge valve, a discharge conveyor and means for driving said discharge valve and discharge conveyor in unison.

3. A rotary drier comprising a rotatable drum, a source of heat supply connected to said drum, a feed conveyor, a material feeding valve disposed to discharge material from said conveyor into one end of said drum, means for driving said feed conveyor and feeding. valve. in unison and a material discharge valve at the other end of. said drum.

HENRY KTRCHMANN,JRl 

